On 10/10/06 13:40, Felix Miata wrote:

On 06/10/10 14:16 (GMT-0500) Greg Wallace apparently typed:

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I've just lost my router. There was a power outage here and the power went on and off 2 or three times. Apparently, that did in my router, even though it was behind a surge protector.

Common surge supressors are mickey mouse junk that need to be replace every 6 months or so. The surge supression built into a UPS is much more reliable. http://computer.howstuffworks.com/surge-protector.htm. This seems to be a rather unapologetic advert for Belkin, but it is nevertheless a good quick reference. AFAIAC, though, on the North American power grid, you need the following levels of protection (I agree with howstuffworks only on the response time):

minimum 1300 joules total power dissipation clamping voltage not exceeding 250 volts 1 nanosecond response time gas discharge tube is essential, to give protection against persistent transients (ie. that last longer than 0.1 seconds, and believe me, on the NA grid, you can see some rather wild stuff for a lot longer than that :-) ). I won't venture a guess on what might be needed on the European power grid, which, IIRC, operates on 220V. Another point is protection of inputs other than the power grid: phone lines, network links, even a TV cable, all of these can be sources of power surges that will destroy your equipment. It is possible, for example, that Greg's router was done in by a spike on the network link rather than the house current. Any decent protector should have coax as well as phone and/or network plugs. I am not convinced that any UPS at all offers acceptable surge protection. Most people don't even bother to look beyond the capacity of the storage battery, and I doubt that your average $50-$75 UPS will give you anywhere near the levels of surge protection I consider adequate (a surge protector alone with that capability can cost the same as, or more than, the least expensive UPS units). howstuffworks.com hints that one might also want to put a surge-only unit in front of the UPS itself. If you have a combination surge/UPS unit that gives adequate protection, it might fail as it protects your electronics, leaving you with some expensive, but useless, dead weight. This also gives you the option of plugging non-essential equipment into something other than the UPS itself, while still protecting all your equipment.

On 10/10/06 16:28, Felix Miata wrote:

On 06/10/10 17:48 (GMT-0400) Darryl Gregorash apparently typed:

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howstuffworks.com hints that one might also want to put a surge-only unit in front of the UPS itself. If you have a combination surge/UPS unit that gives adequate protection, it might fail as it protects your electronics, leaving you with some expensive, but useless, dead weight. This also gives you the option of plugging non-essential equipment into something other than the UPS itself, while still protecting all your equipment.

All the UPS units I've purchased and read the instructions to over the past couple of years have stated that the unit is to be plugged directly into a normal household outlet, not into any type of surge protector. All have provided two types of outlets, surge protect only, and surge protect on backup power. I've only bought one of less than 900VA in recent years. I didn't read that 350 VA's instructions, but it's already history anyway.

I don't know that there is any reason for such a recommendation, other than they want you to have to buy another of their units if the surge protection gets blown away during a storm.

BTW, I live in the lightning capital of the world, central FL, and haven't yet needed to take up any UPS manufacturer on its included connected equipment protection warranty.

I once had a close encounter with a lightning strike, in the days before I gave such things much thought. Nothing died, but my monitor displayed a very nice set of Lissajous figures for about 5 seconds. Then the power went out. The monitor, which was about 3 years old at the time, died about 8 months later, probably a premature death due to stresses it suffered as a result of the lightning. I'm mostly speculating, but this is probably typical of what anyone can expect to encounter: no immediate signs of problems, but equipment starts to die prematurely a few months later, for no apparent cause. The very large surges that will destroy equipment immediately are likely very rarely as a result of lightning. More probably, they will occur during the massive surges that bring down half the grid when some local power company's fault protection fails. If a surge is large enough to start tripping relays at the power company, then you've got a very big problem indeed.

Per Jessen schreef:

Darryl Gregorash wrote:

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I won't venture a guess on what might be needed on the European power grid, which, IIRC, operates on 220V.

Here in Herrliberg, Switzerland we have probably had about one power-outage per year over the last 5 years. There was one year where we even had two. This is unusual - a lot of places might have just one outage over 5 years. Surges - not a problem. Might happen in combination with an outage, but they're minor.

We use no UPS and no surge-suppression - but the write-cache to the RAID-array does have a battery backup.

That used to be the same here in the Netherlands until a couple of years ago when the powers that be surrendered the energy supply to the free market. In contrast to what everybody says this considerable worsened the level of service and we now are on an average of four power outings a year, mostly in the order of, say, half an hour. Yes, they also increased the price. No surges, however and that is the main thing. The power outings are a nuisance to the desktop user, but relatively harmless. For large systems we have a different story of course. Regards, -- Jos van Kan registered Linux user #152704